Cerebrospinal fluid hypovolemia (CSFH) is caused by reducing an amount of cerebrospinal fluid (CSF) due to some causes. A CSFH patient presents with headache, neck pain, dizziness, tinnitus, fatigue or the like as a symptom. In general, CSFH is considered to be treatable; however, CSFH has a problem that it is difficult to diagnose CSFH. Specifically, it is exemplified as a main cause of CSFH that CSF, which fills cerebrospinal cavum around brain and spinal cord, persistently or intermittently leaks out due to high impact on body or head by traffic accident or the like. However the causal relationship between the cause and symptom is hardly specified, since it takes time to experience a symptom from the cause arises.
In order to treat CSFH, it is very important to specify a leakage part of CSF. Specifically, epidural blood patch is effective for treating CSFH caused by a leakage of CSF (Non-patent Documents 1 to 4). In epidural blood patch, autologous blood is injected into extradural space at a leakage part of CSF and coagulated to patch the leakage part. However, when a leakage part of CSF is not specified, epidural blood patch cannot be effectively carried out. It is therefore very important to specify the leakage part for the treatment of CSFH. However, it is very difficult to specify a leakage part of CSF, since a leakage of CSF is persistent and a leakage amount is very small.
When a patient is suspected to have CSFH, firstly, a spine image is generally taken by magnetic resonance imaging (MRI). MRI is safe, since it is not needed in MRI to use a medicine. It is however difficult by MRI to determine whether CSF leaks or not and to specify the leakage part. Then, CSF pressure is measured by lumbar puncture. If CSF pressure is lower than 6 cm H2O, a patient is diagnosed with CSFH. However, a leakage part of CSF cannot be specified by measuring CSF pressure.
In order to specify a leakage part of CSF, computed tomography (CT) myelography and radio isotope (RI) cerebral scintigraphy are generally carried out (Non-patent Document 5). In CT myelography, a contrast medium is injected into bone-marrow space and a diffusion image of the injected contrast medium is taken using X-ray. In RI cerebral scintigraphy, RI is injected into bone-marrow space and an image of a spinae is taken using a gamma camera, by which radiation dose can be recognized. In addition, MRI myelography with using a contrast medium is carried out in some cases. However, as described above, it is very difficult to specify the leakage part, since a leakage amount of CSF is small. In particular, when the leakage part is in upper part of a spine, it is more difficult to specify the leakage part, since a contrast medium and RI are injected by lumbar puncture and the concentrations thereof become lower in upper part of a spine. It is therefore needed to take images multiple times in the diagnosis using the above-described means. Nevertheless, a leakage part of CSF cannot be specified by the above-described means in many cases. According to certain statistics, the rate of specifying a leakage part of CSF by the above-described means is only 10 to 20%. In addition, the above-described means have problems of a side effect by a contrast medium and radiation exposure by RI.